http://reply.papertrans.cn/2/132/13144/13144-31.png
Submitted on: 02 November 2013.
Revised on: 27 February 2014.
Accepted on: 19 March 2014.
___________________International Journal of Chronic Obstructive Pulmonary Disease
Submitted on: 28 August 2003.
Revised on: 03 November 2003.
Accepted on: 06 December 2003.
___________________International Journal of Chronic Obstructive Pulmonary Disease
Submitted on: 07 March 2005.
Revised on: 08 June 2005.
Accepted on: 04 July 2005.
___________________International Journal of Chronic Obstructive Pulmonary Disease
http://reply.papertrans.cn/2/132/13144/13144-35.png
http://reply.papertrans.cn/2/132/13144/13144-36.png